Influence of Gas Medium State Parameters on the Pressure Port Design of Gas Wave Ejector

Objective: The objective of this study is to explore and emphasize the influence mechanism and law of gas parameters on pressure port design. Methods: CFD commercial software FLUENT was used for numerical simulation in this study, and a three-dimensional numerical model was employed to improve the accuracy of calculation. The GWE experimental platform was also built to verify the theoretical and numerical analysis results. Results: When the expansion ratio α is raised from 1.35 to 2.0, the average shock velocity vs can increase by about 4.9%, and when raising the compression ratio from 1.05 to 1.2, the change of vs is only 1.4% relatively. Raising the expansion ratio value from 1.35 to 2.0, the optimal offset of the high- and medium-pressure ports only changes by 5.3%, and the decrease of the ejection rate caused by the deviation of the aforementioned offset is only about 4.3%,which proves that the equipment has strong ability to resist fluctuations of working conditions. Conclusion: Moving velocity of the shock wave varies with temperature, working pressure ratio and adiabatic index of the gas. The increase of high- and low-pressure inlet gas temperatures will cause an increment of vs and as, and the influence of high-pressure inlet gas temperature Tht on vs is greater. There are optimal high- and medium-pressure port offsets under different pressure ratios as the experimental results have shown. When the pressure ratio remains constant, the change in pressure value does not have a significant impact on the optimal port design and equipment performance.